Reversing drive for a tool changer

ABSTRACT

The present invention relates to an improved reversing drive for a tool change mechanism. The improved novel features of this reversing drive are particularly disposed to be incorporated in a tool changer equipped with a pair of tool change arms mounted for pivotal movement in opposite direction from a parked position into enclosed gripping engagement with a pair of spaced apart tools. In addition, the described tool changer particularly adapted to receive the present reversing drive has already included separate power means connected to positively maintain the pivotal arms in original clamped engagement as well as effect bodily movement of the clamped arms to interchange the tools. The reversing drive of this invention includes a single unitary rack having inwardly facing opposed upper and lower rack sections laterally offset a sufficient distance to rotatably drive adjacently journalled gears in opposite direction upon rectilinear movement of the unitary rack in one direction. In addition, one of the laterally offset rack sections of the present invention incorporates an axially extending rack section that is relatively positionable to function as a transfer device for simultaneously engaging the synchronized teeth of both oppositely rotated concentric gears to maintain them in preset angular positions during axial movement relative thereto.

United States Patent [191 Kirkham [4 1 Jan. 22, 1974 PrimaryExaminer-Gerald M. Forlenza Assistant Examiner-George F. AbrahamAttorney, Agent, or Firm-Cyril M. Hajewski [57] ABSTRACT The presentinvention relates to an improved reversing drive for a tool changemechanism. The improved novel features of this reversing drive areparticularly disposed to be incorporated in a tool changer equipped witha pair of tool change arms mounted for pivotal movement in oppositedirection from a parked position into enclosed gripping engagement witha pair of spaced apart tools. In addition, the described tool changerparticularly adapted to receive the present reversing drive has alreadyincluded separate power means connected to positively maintain thepivotal arms in original clamped engagement as well as effect bodilymovement of the clamped arms to interchange the tools. The reversingdrive of this invention includes a single unitary rack having inwardlyfacing opposed upper and lower rack sections laterally offset asufficient distance to rotatably drive adjacently journalled gears inopposite direction upon rectilinear movement of the unitary rack in onedirection. In addition, one of the laterally offset rack sections of thepresent invention incorporates an axially extending rack section that isrelatively positionable to function as a transfer device forsimultaneously engaging the synchronized teeth of both oppositelyrotated concentric gears to maintain them in preset angular positionsduring axial movement relative thereto.

3 Claims, 2 Drawing Figures BACKGROUND OF THE INVENTION The arrangementfor providing two separate drives for first rotating a pair of pivotaltool change arms in reverse directions to effect tool clamping, andsecond, moving both clamped arms in the same direction to bodilyinterchange the positions of the clamped tools is shown for the firsttime in a co-pending patent application. As there shown, a pair ofpivotal tool change arms are initially rotated in opposite directionsfrom parked to tool enclosing clamped positions. After this, the clampedarms are moved axially outward to extract the clamped tools and thenrotated 180 in the same direction to interchange the positions of theclamped tools. Reverse input control of the reversibly journalled toolengaging arms is provided by concentrically and re- .motely journalledgears respectively interconnected to drive the arms by axially extendingconcentric drive sleeves. The unitary rack of the present reversingdrive further consolidates and simplifies the transmission means forsupplying input power to reversibly drive a pair of pivotal arms inopposite directions.

SUMMARY OF THE INVENTION According to this invention, there is provided.an improved and simplified transmission for simultaneously rotatingadjacently journalled gears in reverse directions. Essentially, thedrive comprises a unitary and rectilinearly movable rack configured topresent laterally adjacent, inwardly facing upper and lower opposed racksections that respectively engage the opposite outer peripheral edges ofthe adjacent gears. By means of this arrangement, rectilinear transversemovement of the unitary rack in one direction simultaneously rotates therespective adjacently journalledv gears in opposite directions.Furthermore, the unitary rack is adapted to be positively locked againstrectilinear movement to position the axially elongated teeth of one racksection for intermeshing with the oppositely rotatable gear as the teethof that gear are moved axially in. synchronized relationship with thealready engaged gear being moved in like axial direction.

It is a general object of the present invention to provide a greatlyimproved reverse drive for rotatably driving adjacent gears in oppositedirections.

It is another object of the invention to provide an improved unitaryrack having laterally adjacent, and vertically spaced opposed racksections so configured as to rotate adjacently journalled gears inopposite directions, and having one axially extending rack sectionrelatively positionable in an axial direction to simultaneously engagethe rotatably synchronized teeth of both gears.

It is a further object of the invention to provide an improved unitaryreversing drive for rotating adjacent pivotal tool change arms inopposite directions from a parked position into clamped engagement withspaced apart tools.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged fragmentaryview, partly in elevation and partly in horizontal section through adrive mechanism incorporating the invention; and

FIG. 2 is an enlarged fragmentary view in perspective of the applicantsinvention and with parts broken away to clearly illustrate the unitaryreverse drive means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingsand particularly to FIGS. 1 and 2 thereof, an improved reverse controldrive mechanism is there illustrated as providing reversible input powerto the oppositely rotatable tool change arms of a mchine tool. Toreceive driving power for being selectively rotated in oppositedirections or connected for simultaneous rotation in the same direction,there are provided concentric and independently rotatable gears 10 and11. The forward concentric gear 10 is positively secured to an outertubular drive sleeve 14 that in turn is secured at its forward end to arearwardly positioned large diameter tool change arm 15. The arrangementis such that rotation of the forwardly positioned gear 10 in either aclockwise or counterclockwise direction effects rotation of the outertubular sleeve 14 and tool change arm 15 as a single unit in acorresponding clockwise or counterclockwise direction.

In a similar manner, a rearwardly adjacent and concentricallly formeddrive gear 11' is positively secured to a forwardly extendingconcentrically formed drive shaft 18 that in turn is positively splinedat its forward end to a forwardly positioned, smaller diameter toolchanger arm 19. A forwardly positioned hub 20 is secured to theforwardly extending inner drive shaft 18 in a manner to maintain therespective tool change arms 19 and 15 in adjacent concentric positionsfor selective reverse rotation in opposite directions, or simultaneousrotation in the same direction.

Actually, the independently rotatable tool change arms or grips l5 and19 comprise a single tool change mechanism 22 operative to effect abodily interchange of a pair of spaced apart tools, such as 24 and 25,respectively carried in a horizontally spaced apart operating spindle 26and a storage spindle 27. The spaced apart spindles 26 and 27 aremovable from prior positions to the exact horizontally spaced apartpositions shown in well-known manner at the atart of any tool changingoperating cycle. To grasp tools for effecting an interchange, theseparate independently journalled tool change arms 15 and 19 arerespectively provided at their opposite ends with cooperatively disposedsemicircular openings. The arrangement is such that upon beginning atool changing operation, the arms 15 and 19 are respectively andcoordinately rotated in reverse directions. Thus, the inner or smalldiameter forward arm 19 is rotated from vertical parked position adistance of 90 in a clockwise direction as viewed from the front of themachine. At the same time, the larger diameter outer arm 15 is rotatedfrom vertical parked position a distance of 90 in a counterclockwisedirection. As a result, the semicircular open-ings respectively providedat the opposite ends of the arms 19 and 15 are moved into horizontallyopposed tool enclosing clamped engagement with the respective tools 24and 25.

After the arms are rotated into 90 clamped engagement with therespective tools, the entire horizontally disposed assembly 22,including arms 19 and 15, is moved axially forward to fully extract bothof the clamped tools 24 and 25 from the respectively spaced apart toolreceiving stations or spindles 26 and 27. Next, with the tools thenfully withdrawn from the respective stations, the entire assembly may berotated 180 in a clockwise direction to reposition the clamped tools.Upon completion of this movement, retracted tool 25 is moved 180 intoalignment with the spindle 26 for insertion therein, and the retractedtool 24 is moved 180 into alignment with the storage station 27 forinsertion therein. After effecting 180 rotation of the entire forwardlymoved tool changer assembly 22, the arrangement is such that the entireassembly is moved axiallyinward to reinsert the now interchanged tools.After this, the respectively clamped tool change arms 15 and 19 are eachrotated 90 in reverse direction from their still clamped horizontalpositions in a manner to return the arms to vertical parked position asillustrated in FIG. 2.

Although this entire double clamp arm gripping arrangement of thechanger mechanism 22 has been described in considerable detail in theaforementioned co-pending patent application to Earl R. Lohneis, thepresent reverse drive mechanism is particularly adapted to provide animproved method of supplying selective reverse drive to the inputdriving mechanism as well as controlled clamped engagement during axialmovement.

To reversibly drive concentrically journalled gears and 11, .there isprovided a greatly improved transversely slidable unitary rack structure30. Acutally, the lineally movable unitary rack structure 30 is providedwith an upper lineal rack section 31 having downwardly extending rackteeth in meshing engagement with the teeth presented by a rearwardlyjournalled gear 11. The upper lineal rack section 31 is secured to aparallel and laterally offset, axially elongated rack section 32 bymeans of transversely spaced apart vertical wall sections SUV-30Vrespectively secured at their lower ends to a transverse wall 30L joinedto the base of rack section 32. In effect, the downwardly facing teethof upper rack section 31 are fixedly secured relative to the verticallyspaced apart upwardly facing rack teeth of laterally offset rack 32 toprovide one unitary rack structure 30 joined together to provide reverseinput driving power to the spaced apart gears 10 and 11.

Attention is directed to the fact that the vertically extending walls30V-30V of the unitary rack structure 30 are transversely spaced apart asufficient distance to provide an enlarged transversely formed,rectangular opening 36 permitting passage of a reduced diameter pistonrod 54 rotatably secured to the gear 11. To do this, the piston rod 54is provided with a flanged end 545 rotatably journalled in a bearing 54Bfixedly secured to the hub of gear 1 l. The associated supportingmachine tool structure 38 is provided with a pair of transverselyextending rectangular guides 39 and 40 adapted to slidably engagecomplimentary guideways presented at opposite sides of the unitary rackstructure 30 in well-known manner. The rearward rectangular guideway 40is secured to a transversely extending end wall 41 that, in turn,fixedly secured to the support structure 38 of the machine. An axiallyforward, parallel rack 43 for effecting simultaneous rotation of bothgears 10 and 11 in the same direction is mounted for transverselyslidable movement on rectangular guideways 45 and 39. Rectangularguideway 45 is secured to the frame structure 38 in a manner similar tothe spaced apart rectangular guideway 39.

Initially, to effect 90 reverse rotation of the input drive gears 10 and11 in opposite directions, a circuit transverse movement of the unitaryrack structure 30 is adapted to effect corresponding movement of thespaced apart opposed rack sections 31 and 32 to respectively rotategears 10 and 11 in opposite directions at a one-to-one ratio. Thedescribed rectilinear movement of unitary rack structure 30 is adaptedto simultaneously effect movement of the separate tool change arms 19and 15 in a clockwise and counterclockwise direction respectively. Uponarrival of the unitary rack structure 30 at its predetermined limit oftransverse movement, a limit switch (not shown) is actuated to bothmaintain the cylinder 48 at its pressure-actuated limit of forwardmovement, and activate the hydraulic circuit to supply pressure fluid toan inlet cylinder 53.

Actuation of cylinder 53 as described effects axial forward movement ofa piston rod 54 which is connected to effect coordinated axial forwardmovement of the now angularly clamped gears 10 and 11 as well as theassociated tubular shafts l8 and 14 which are connected to therespective tool change arms 15 and 19. Thus, it will be apparent thetool change arms move axially outward in their now horizontally clampedposition to extract the spaced apart tools 24 and 25 from the respectivetoolholder sockets.

As axial forward movement is effected, the angularly clamped gears 10and 11 are both moved axially forward into meshing engagement with theaxially extending teeth of parallel rack section 32. Thus, the axiallyextending or elongated teeth 32 of the unitary rack structure 30 nowfunction as an axial guide to maintain both gears 10 and 11 inoriginally clamped and synchronized positions until they move intomeshing engagement with the axially spaced apart, or control rack 43.Upon arrival of the angularly clamped gears 10 and 11 in axially forwardposition indicated at 108 and 11S, pressure fluid is directed to aninlet 57 of cylinder 58. Actuation of the cylinder 58, as described,urges an associated piston rod 59 forward to effect correspondingtransverse movement of the rack 43 to effect simultaneous rotation ofthe synchronized, clamped gears 10S and 118 a distance of 180 in thesame direction to effect a corresponding 180 inter changed rotation ofthe axially extracted tools carried by the clamped tool change arms 15and 19. During this 180 rotation, it will be understood that therespective gears 10 and 11 are continuously retained in originallyclamped position as initially effected by transverse movement of theunitary rack structure 30.

With the axially extracted and angularly clamped tool change arms 15, 19in 180 interchanged position relative to the sockets 26 and 27, axialinserting movement of the respectively interchanged tools can beeffected by activating the hydraulic circuit to supply pressure fluid toinlet 62 of rearwardly positioned axial stationary cylinder 53. lnwardmovement of the still clamped changer arms 19 and 15 to reinsert theinterchanged tools is effected by corresponding axial inward movement ofthe axially extending piston rod 54 due to the rotatable connection ofpiston rod flange 54E to the flanged bearing 54B secured to gear 11.During the axial inserting stroke of the entire clamped tool changeassembly 22, the still clamped gears and 11 are maintained in originallyclamped position by engagement of the teeth presented by gears 10 and 11with the axially elongated rotatably stationary meshing teeth of thetransfer rack section 32. Upon arrival of the tool change assembly inits fully inserted position, the respectively associated clamped gears10 and 11 are returned into the rearward axial positions illustrated inFIG. 1. As there shown, the rearward gear 11 connected to the innertubular drive sleeve 18 is returned into meshing engagement with theupper rack section 31 of unitary rack structure 30. At the same time,the concentrically journalled drive gear 10 connected to drive the outertubular sleeve 14 is still maintained in meshing engagement with theteeth of the parallel lower rack section 32 of the unitary rackstructure 30. Inasmuch as the respective gears are now in reversiblemeshing engagement with the opposed, vertically spaced apart andlaterally offset rack sections of the unitary rack structure 30, acondition has been reestablished for returning the clamped tool changearms 19 and from horizontal position to original vertically parkedposition. This condition is achieved by reactivating the hydrauliccircuit to supply pressure fluid to a forward inlet 64 associated withthe 90 cylinder 48. At the same time, pressure fluid is supplied to aninlet 65 of cylinder 58. Thus, hydraulic fluid supplied to inlets 64 and65 effect rightward rearward movement of the respectively associatedpiston rods 49 and 59, thereby moving unitary rack structure 30 and 180rack 43 to the limit of rightward movement. This returns both rackstructures to rightward position facilitating a restarting of the nexttool change cycle in the manner hereinbefore described.

Although not shown in the drawings, it will be understood that limitswitches are connected to be actuated by movement of the respectiverectilinearly movable members including piston rods 49, 54 and 59 in theusual manner. It will likewise be understood that in all cases,adjusting plugs (not shown) are coordinately preset to limit the axialmovement of each of the axially movable racks and associated piston rodsas required. In all cases likewise, the preset rectilinear adjustment ofthe adjusting plugs is coordinated with the operation of the associatedlimit switch for that particular axis.

Although the illustrative embodiments of this invention have beendescribed in considerable detail for the purpose of disclosing apractical operating structure whereby the invention may be practicedadvantageously, it is to be understood that the particular apparatusdescribed is intended to be illustrative only and that the various novelcharacteristics of the invention may be incorporated in other structuralforms without departing from the spirit and scope of the invention asdefined in the subjoined claims.

What I claim is:

I. In a drive mechanism for driving a tool transfer member thatcomprises a pair of cooperating tool change arms with each having atleast one grip;

a first drive shaft rotatably supported by said frame and con-nected torotate the first of said tool change arms;

a first gear connected to rotate with said first drive shaft;

a second drive shaft rotatably supported by said frame and con-nected torotate the second of said tool change arms;

a second gear connected to rotate said second drive shaft;

a first gear rack in meshing engagement with said first gear;

a second gear rack connected for movement in unison with said first gearrack and being in meshing engagement with said second gear in positionso that the unitary movement of said gear racks will cause said firstand second gears to rotate in opposite directions for rotating said toolchange arms in opposite directions to move their cooperating gripseither toward each other into engagement with a tool for securing thetool to said transfer member, or for moving said grips away from eachother for releasing a tool;

actuating means connected to actuate said gear racks in unison in eitherdirection for producing the rotation of said first and second gears andtheir associated tool change arms;

a third gear rack in alignment with said first gear rack;

shifting means connected to shift said first and second gears in unisoninto simultaneous engagement with said third gear rack; and

second actuating means connected to actuate said third gear rack ineither direction for producing simultaneous rotation of said first andsecond gears in the same direction to produce a like simultaneousrotation of said tool change arms for transferring a gripped tool fromone position to another.

2. A drive mechanism according to claim 1 including locking meanspreventing relative rotation of said first and second gears during theshifting movement toward and away from said third gear rack so that saidtool change arms are locked in their positions-with respect to eachother to maintain a gripped tool secured to said tool change arms duringthe transfer movement.

3. A drive mechanism according to claim 2 wherein said locking meanscomprises elongated teeth on said first gear rack, and as said first andsecond gears are shifted toward said third gear rack, said first gearremains in meshing engagement with said elongated teeth and said secondgear is moved into meshing engagement with said elongated teeth to locksaid first and second gears together during the shifting movement.

1. In a drive mechanism for driving a tool transfer member thatcomprises a pair of cooperating tool change arms with each having atleast one grip; a first drive shaft rotatably supported by said frameand connected to rotate the first of said tool change arms; a first gearconnected to rotate with said first drive shaft; a second drive shaftrotatably supported by said frame and connected to rotate the second ofsaid tool change arms; a second gear connected to rotate said seconddrive shaft; a first gear rack in meshing engagement with said firstgear; a second gear rack connected for movement in unison with saidfirst gear rack and being in meshing engagement with said second gear inposition so that the unitary movement of said gear racks will cause saidfirst and second gears to rotate in opposite directions for rotatingsaid tool change arms in opposite directions to move their cooperatinggrips either toward each other into engagement with a tool for securingthe tool to said transfer member, or for moving said grips away fromeach other for releasing a tool; actuating means connected to actuatesaid gear racks in unison in either direction for producing the rotationof said first and second gears aNd their associated tool change arms; athird gear rack in alignment with said first gear rack; shifting meansconnected to shift said first and second gears in unison intosimultaneous engagement with said third gear rack; and second actuatingmeans connected to actuate said third gear rack in either direction forproducing simultaneous rotation of said first and second gears in thesame direction to produce a like simultaneous rotation of said toolchange arms for transferring a gripped tool from one position toanother.
 2. A drive mechanism according to claim 1 including lockingmeans preventing relative rotation of said first and second gears duringthe shifting movement toward and away from said third gear rack so thatsaid tool change arms are locked in their positions with respect to eachother to maintain a gripped tool secured to said tool change arms duringthe transfer movement.
 3. A drive mechanism according to claim 2 whereinsaid locking means comprises elongated teeth on said first gear rack,and as said first and second gears are shifted toward said third gearrack, said first gear remains in meshing engagement with said elongatedteeth and said second gear is moved into meshing engagement with saidelongated teeth to lock said first and second gears together during theshifting movement.